Fluorinated 1,3-benzothiazin-4-ones containing fluoroquinolone fragment

Chemistry of Heterocyclic Compounds - We have developed an efficient synthetic approach to potential antibacterial agents with double mechanism of action through the combination of antibacterial...     

Pericyclic reactions in the synthesis of new 5-aryl-5,6-dihydroquinolino[2,1-b]quinazolin-12-ones

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Synthesis and Biological Activity of 2-Aryl-4-hydroxy-4-methyl-6-oxocyclohexane-1,3-dicarboxamides

Russian Journal of General Chemistry - The reaction of unsubstituted acetoacetamide with aromatic aldehydes in ethanol in the presence of piperidine gave...     

Structural trends of 29Si–1H spin–spin coupling constants across double bond

The calculations of geminal and vicinal ²⁹Si–¹H spin–spin coupling constants across double bond in 15 alkenylmethylsilanes and alkenylchlorosilanes were carried out at the second‐order polarization propagator approach level in a good agreement with experiment. Two structural trends, namely, (i) the geometry of the coupling pathway and (ii) the effect of the electrowithdrawing substituent, have been interpreted in terms of the natural J‐coupling analysis within the framework of the natural bond orbital approach. Thus, the marked difference between cisoidal and transoidal ²⁹Si–¹H spin–spin coupling constants across double bond was accounted for the delocalization contributions including bonding and antibonding Si–C and C–H orbitals, whereas the chlorine effect was explained in terms of the steric contributions including bonding Si–Cl orbitals. Copyright © 2012 John Wiley & Sons, Ltd.     

Oblique collision of a plane-polarized Alfvén discontinuity and a slow shock wave propagating in opposite directions in magnetohydrodynamics

Collision of plane fronts of a plane-polarized Alfvén discontinuity and a slow shock wave propagating in opposite directions at a certain angle is considered within the framework of an ideal magnetohydrodynamic model. The initial state of an infinitely conducting medium at rest with a frozen-in magnetic field is assumed to be given. Calculations are carried out for various values of the shock wave Mach number and the magnetic field strength using a special software which makes it possible to find an exact solution of the Riemann problem of breakdown of a discontinuity between the states downstream of the interacting waves by means of a computer. The wave flow structure is investigated and a bifurcation map of flow restructuring is constructed. Domains of the initial parameters for which the interaction differs qualitatively are distinguished. The parameters of the medium and magnetic field are found as functions of the angle between the colliding discontinuities and the inclination of the magnetic field. The results obtained may be used in investigations of magnetic reconnection.     

2-Hydroxybenzaldehyde (2-phenylquinazolin-4-yl)hydrazones and their ZnII complexes: synthesis and photophysical properties

N-(2-Phenylquinazolin-4-yl)-N??-salicylidenehydrazines and their Zn^II complexes were obtained. The structures and luminescent properties of these new quinazoline derivatives were examined.     

Synthesis and photophysical properties of 2-styrylquinazolin-4-ones

trans-2-Styryl-substituted 3H-, 3-phenyl-, and 3-naphthylquinazolin-4-ones and their 6,7-difluoro derivatives were synthesized by condensation of appropriate 2-methylquinazolin-4-ones with aromatic aldehydes or by the transformation of the heterocycle of 2-methyl-3,1-benzoxazin-4-one under the action of benzylidenephenylamines.     

Synthesis of Fluorinated 1,3,4-Oxadiazino[6,5,4-i,j]quinolines

3-(2-Acylhydrazino)-2-tetra(penta)fluorobenzoylacrylates are readily converted to acylamino-substituted quinolones and, under more forcing conditions, annelation of oxadiazine ring occurs. We have identified the possible cyclization of the mentioned acrylates to 4,5-substituted pyrazoles.     

A highly efficient white-light-emitting diode based on a two-component polyfluorene/quantum dot composite

Organic light-emitting diodes (OLEDs) are attracting great interest of the scientific community and industry because they can be grown on flexible substrates using relatively simple and inexpensive technologies (solution processes). However, a problem in the fabrication of white OLEDs is that it is difficult to achieve a balance between the intensities of individual emission components in the blue, green, and red spectral regions. In this work, we try to solve this problem by creating a two-component light-emitting diode based on modified polyfluorene (PF-BT), which efficiently emits in the blue–green region, and CdSe/ZnS/CdS/ZnS semiconductor quantum dots emitting in the orange–red region with a fluorescence quantum yield exceeding 90%. By changing the mass ratio of components in the active light-emitting composite within 40–50%, it is possible to transform the diode emission spectrum from cold to warm white light without loss of the diode efficiency. It is very likely that optimization of the morphology of multilayer light-emitting diodes will lead to further improvement of their characteristics.     

Erratum to: “A highly efficient white-light-emitting diode based on a two-component polyfluorene/quantum dot composite”

Optics and Spectroscopy -